The impending retirement of thousands of business owners presents an economic challenge for Long Island and the nation because most haven't made plans for what happens after they leave.

Studies estimate more than half of all privately held companies are run by baby boomers and 80 percent expect to sell or close them within the next 10 years. The statistics were cited Tuesday night by a panel of local financial and estate planners.

"Seventy-five percent of companies -- and some estimates are higher -- don't sell," said panelist Jesse Giordano, a financial planner with Morgan Stanley Wealth Management in Great Neck. "The owners just close the doors and walk away."

He said this often happens because business owners haven't prepared a family member or manager to succeed them, aren't psychologically ready for retirement or haven't considered how they will support themselves in old age.

"The biggest obstacle that we often run into is the owner doesn't have an answer to the question 'What am I going to do next?' " he said.

Giordano and two other panelists spoke to about 50 executives after a dinner at Carlyle on the Green in Farmingdale. The panel discussion was the first in a series organized by the New York Chapter of the Association for Corporate Growth, a group of investors, bankers, lawyers and accountants who work with medium-sized companies.

The emotional toll of leaving an enterprise that you own is underestimated, said Harry Armon, a serial entrepreneur and president of the estate planning firm ARCAP Partners in Jericho.

"Until you come to grips with not identifying with that business, not making it part of your body, part of your soul -- you cannot begin to plan for retirement," he said.

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Last year, Armon and two partners opened the restaurant Doppio Artisan Bistro in Huntington Village.

Armon's career began in his family's defense contracting business. The Nassau County-based company, which he declined to identify, employed 1,100 people in five states before acrimony within the family led to its dissolution in 2011.

"It didn't end well," recalled Armon. "What I learned is that you have to have a professional management team. Most family-run companies are a one-man show, and private equity investors, potential buyers -- they want to see that the company is organized in such a way that it can continue after the owner retires."

Crucial to all of this is that the business owner becomes acclimated to leaving.

Dr. Arnold Levy, a psychiatrist in Roslyn, said he often holds counseling sessions with owners and their spouses. "Owners feel anxious, afraid, depressed," he said. "They don't know what they are retiring to."